In a vertical baler for scrap material, for example, of the type disclosed in U.S. Pat. No. 3,851,577 now assigned to the assignee of the present invention, a generally rectangular compacting chamber is defined between parallel spaced vertical end walls mounted on a base forming a bottom wall, and the rear wall for the chamber is formed by a series of parallel spaced channel members defining vertical slots therebetween. One or two front doors are pivotally connected to the end walls and form the front wall of the compacting chamber. A horizontal rectangular platen is suspended within the chamber by the ram or piston rod of a vertical hydraulic cylinder which is supported by a frame forming the top wall of the baler. The opposing bottom wall and platen are each provided with means defining parallel spaced slots which align with the slots in the rear wall and provide for extending tie cords or wires around a bale of material while the bale remains compacted by the platen and after the front doors are opened.
In such a baler, it has been found desirable to provide the front doors and back wall with triangular shaped hold-down teeth or fixed dog members which maintain some compaction of the material when the platen is raised for receiving another batch of scrap material supplied to the chamber through an opening above the front doors of the baler. As disclosed in the above patent, it has also been found desirable to provide a vertical baler with a set of flexible bale ejecting members which extend across the bottom wall of the baler through the slots in the back wall and are adapted to be hooked onto the platen after a bale is tied. When the platen is elevated or retracted upwardly, the flexible ejecting members roll the bale out of the compacting chamber and onto some means for transporting the bale such as a wheeled cart. A problem arises when the material hold-down dog members are made relatively large to make them more effective in holding down the compacted material when the platen is raised for receiving additional material. If the dog members are not retracted before a tied bale is ejected, the platen and ejecting members may be subjected to substantial stress which can easily break a flexible ejecting member or damage the platen and its supporting hydraulic cylinder.